"Nature wants children to be children before they are adults.
If we deliberately depart from this order, we shall get premature fruits
which are neither ripe nor well flavored and which soon decay.
We shall have youthful sages and grown up children.
Childhood has ways of seeing, thinking, and feeling, peculiar to itself;
Nothing can be more foolish than to substitute our ways for theirs."
Make sure the activity, group or program you are running is truly for children. Avoid delivering adult information. Modify the way you speak. Have lots of fun. Make it experiential. If it's not, it's not for kids. As the quote reminds us,
don't substitute our ways for theirs.